Want a sure-fire way to get your customers to open your direct-mail piece? Try this technique that nobody can resist: Customers will always open an envelope with a lump in it or a small box of anything. Put a swatch or sample of a new product you want to promote inside an envelope. Obviously , some products just can't be squeezed in, but don't worry. Just include something that relates to your product or something that you can play off of in a product announcement. For instance, a not saying, "If you want to test the new phone system, just whistle" could accompany a bright, shiny whistle.
Excerpted from 303 Marketing Tips: Guaranteed To Boost Your Business